2016 SEAOC CONVENTION PROCEEDINGS

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SEAOC EPEP After-Action Retrospective: 2014 South Napa Earthquake

Scott M. Adan, Ph.D., SE, SECB

Director of Seismic Assessment Services, CBRE and Principal, Adan Engineering, LLC

Santa Monica, CA

Jeff P. Hunt, Ph.D., PE Managing Engineer

Exponent Failure Analysis Associates Orange County, CA

Abstract The Post-Disaster Performance Observation Committee (PDPOC) manages and supports SEAOC’s Earthquake Performance Evaluation Program (EPEP). EPEP’s mission is to systematically gather engineering observations and information following an earthquake to enable evaluation of the structural and nonstructural performance of buildings near strong motion recording stations. By systematically collecting observations on both poor and well performing structures, the PDPOC is able to build a more complete building performance data set to reduce uncertainties in observed performance and help calibrate performance-based engineering by defining/refining fragility functions for building structural systems and components. Following the August 23, 2014 South Napa earthquake, EPEP was deployed in and around the city of Napa, California. The deployment was mobilized to select locations or pods within the affected zone. A pod includes buildings and structures within a 500-1000 feet radius of a strong motion station. The initial stage (phase 1) of the deployment included a volunteer effort to observe and survey each of the selected pods, assessing both structural and where possible non-structural damage. The phase 1 assessments are intended to provide preliminary global building performance data as well as to identify candidate buildings for more detailed phase 2 and 3 investigations and studies, respectively. Utilizing the ground motion records, the phase 1 assessment also provided the opportunity to correlate seismic intensity measures and severity of damage. The correlations are based on both building class and vintage of construction. The phase 2 investigations, performed on select buildings, include

additional follow-up observations and review of available construction documentation. The phase 3 studies include in-depth analyses to examine both expected and actual building performance and document its variability. Introduction The SEAOC’s Earthquake Performance Evaluation Program (EPEP) is supported by the SEAOC Post-Disaster Performance Observation Committee (PDPOC), a subcommittee of SEAOC’s Existing Building Committee. In response to a recommendation by SEAOC’s Vision 2000, the PDPOC was established in 2006 to gather building performance information that can be directly correlated to measured ground motions. Following an earthquake, personnel are deployed to survey all buildings within a “pod” around a ground motion recording station that registered minimum ground motion intensity triggers. A pod includes buildings and structures within a 500-1000 feet radius of a Strong-Motion Instrument Program (SMIP) station. The deployment triggers are a minimum peak ground acceleration of 0.20g and a minimum peak ground velocity of 20 cm/sec. During this survey a “short form” is completed for all buildings in each pod, regardless of whether they were damaged or not. The formwork is based on the methodologies developed in the ATC-38 report, Database on the Performance of Structures near Strong-Motion Recordings: 1994 Northridge California Earthquake (ATC, 2000). The ATC-38 methodology was developed following the 1994 Northridge earthquake to systematically collect and analyze data from buildings located within the designated pod. The

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forms were created to collect data including structure size, age, location, structural framing system and other important structural characteristics, nonstructural systems and performance. Information on post-earthquake damage evaluations and placarding is also collected. In addition, photos of the each building within the pod are taken and cataloged. By systematically observing the behavior of both poor and well performing structures in close proximity to recorded ground motions, PDPOC is able to collect data that can be used for statistical and analytical studies. For example, the data gathered by the PDPOC can be used to develop and refine fragility functions that establish relationships between seismic intensity (PGA, PGV) and observed damage (e.g. shear cracks in brick masonry walls, anchor failures in retrofitted URM buildings, cracking of drywall, overturning of equipment, etc.). As the structural engineering community moves more towards performance based analysis and design (as exemplified with the adoption of the Risk Targeted Ground Motions in ASCE 7-10 and the more widespread adoption of performance based approaches used by ATC-58, FEMA P695, HAZUS, etc.), it is becoming particularly important to gather data that directly relates building performance to ground motion intensity measures (SEAOC 2016). 2014 South Napa Earthquake The magnitude-6.0 South Napa Earthquake occurred on August 24, 2014 at 3:20 am (PST) with an epicenter located approximately 8.0 km (5.0 miles) south-southwest of Napa. The quake was felt widely throughout the northern San Francisco Bay Area, with the most severe shaking recorded in the cities of Napa, American Canyon and Vallejo. The hypocenter was located at a depth of 10.0 km (6.3 miles). Significant shaking generally lasted less than 10 seconds depending on location. In downtown Napa, the SMIP station recorded approximately 6 seconds of strong ground motion (GEER, 2014). The event was the largest in the San Francisco Bay Area since the 1989 Loma Prieta earthquake with accompanying maximum Mercalli intensities between VIII and IX (Figure 1). Significant damage to structures and disruption to businesses were reported; one fatality and approximately 200 injuries were attributed to the earthquake. Total damage in the southern Napa Valley and Vallejo areas was in the range of $363 million to 1 billion. One person was killed and 200 injured.

Figure 1. USGS shake map (USGS 2014). As shown in Figure 2, the earthquake fractured the ground surface along several strands of the West Napa fault zone, a 43-km-long zone of discontinuous faulting. The west Napa fault is part of the system of northwest-trending faults in the San Francisco Bay region. EPEP Phase 1 Deployment SMIP recorded the earthquake at six stations in around the affected area. Each station’s strong motion records and other associated information was then processed and disseminated to the engineering community. EPEP was subsequently deployed to the six designated pods. The initial stage (phase 1) of the deployment included a volunteer effort to observe and survey each of the six selected pods. However, given the dense urban location, the level of ground shaking and associated damage, the main focus was placed on the pod located at 902 Main Street (Downtown Joe’s Brewery and Restaurant), referred to as the Main Street pod. Figure 3 shows the location of the pod. In this case, the pod diameter was set to 750 feet. However, reconnaissance work included collection of data for select buildings outside of the set radius in order to more comprehensively assess the nature and scope of building performance.

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Figure 2. San Francisco Bay regional fault map (Bay Area News Group 2014).

Figure 3. Main Street pod, with a 750-feet radius (red line). Within the Main Street pod, there are a significant number of commercial and civic buildings, both historic and modern. The pod also includes a significant number of unreinforced masonry (URM) buildings, many that have been retrofitted.

The Main Street SMIP station is approximately 3.9 km (2.4 miles) from the earthquake epicenter. The recorded peak ground accelerations (PGA) were 0.61g (north-south) and 0.32g (east-west) (GEER, 2014). Figures 4(a) and (b) show the code based versus recorded spectral responses in the north-south and east-west directions, respectively. In the figures, GEER compared the recorded ground motions to the code –based design spectra.

(a)

(b)

Figure 4. Main Street (NCN016) code-based vs. recorded response spectrum (a) north-south; (b) east-west (GEER 2014). The soils underlying the pod and the downtown region in general are consistently alluvial in nature. Alluvium is primarily loose, unconsolidated soil, which has been eroded, reshaped by water, and redeposited, in a non-marine setting. Most if not all, alluvium is very young (Quaternary in age) and is often referred to as “cover” because these deposits tend to obscure the underlying bedrock. The soil classification most associated with these deposits is type “D” (stiff soil) in

Legend

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accordance with the National Earthquake Hazards Reduction Program (NEHRP, 2016). Main Street Pod Deployment Summary The objective of the deployment was to collect the pertinent ATC-38 data for as many buildings within the pod boundaries as possible. The deployment occurred on Friday, August 29, 2014. Scott Adan and Fred Turner, both members of the SEAOC PDPOC conducted the initial deployment. A recent follow-up deployment occurred on Monday, May 23, 2016. Scott Adan conducted the follow-up survey. In the initial deployment, a total of 42 buildings were surveyed within the Main Street pod. A total of 14 buildings (33%) included both interior and exterior surveys with the remaining 28 (67%) receiving only exterior surveys. The follow-up survey was limited to only exterior observations. Dates of construction in the surveyed area varied between 1878 and 2009. The pod included a number of historical buildings. Buildings ranged in height from one to four stories with the majority (45%) being single story. The majority of buildings (69%) include some type of retail or mixed-use space with the next most common being civic (14%) and office (12%). In terms of model buildings types, unreinforced masonry (URM) structures made up almost half of the inventory (48%). As shown in Figure 5, a range of other types was also represented.

Figure 5. Main Street pod ASCE 41 building types.

Distribution of building structural damage is shown in Figure 6. Overall, heavy structural damage was observed in only 10% of the buildings, while minor to moderate damage in 33%. The remaining 60% of buildings were observed with either insignificant or no damage. In general, heavy and moderate damage was confined to URM buildings. Furthermore, fully retrofitted URM buildings were observed with less damaged than those with only partial or no retrofit upgrades.

Figure 6. Main Street pod structural damage severity. With respect to non-structural damage, accurate assessments were limited due to the lack of adequate access. A further and more comprehensive breakdown of both structural and non-structural damage both inside and outside the pod area is presented in FEMA P-1024 (FEMA 2015). In terms of placards, 21% of the buildings were posted “Unsafe,” and 26% with “Restricted Use.” The remaining buildings were either posted “Inspected” (21%), or not posted (31%). Efforts Beyond Phase 1 Following the initial deployment, further consideration, investigation and evaluation proceeded on select buildings within the pod. The remaining sections highlight several of these further developments. They were chosen to illustrate representative development beyond phase 1, and include both buildings that sustained significant damage, as well as those with little or no damage. 1219 1st Street (Goodman Library) Built in 1901, the Goodman Library, is a two-story retrofitted stone masonry building. The building was partially retrofitted in 1975 and then more comprehensively in 2004, following

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damage sustained in the 2000 Younteville earthquake. The federally funded 2004 retrofit was designed in accordance with the 1997 Uniform Code for Building Conservation (ICBO, 1997). The retrofit included the installation of tension and shear ties, parapet strengthening, and the installation of a concrete shear wall behind the front façade. Reportedly, retrofitting of the turret was limited to avoid compromising the building’s historical integrity. During the earthquake, as shown in Photo 1, the building’s stone masonry turret was significantly cracked and damaged. In addition, it was reported that excessive outward movement and damage occurred at all four building corners (FEMA 2015). The building was posted “Unsafe.”

Photo 1. Goodman Library turret and front façade damage. Subsequent to the damage, the building was targeted for phase 2 and 3 investigations. California’s SMART (State Mitigation Assessment Review Team) in collaboration with the Office of Emergency Management (Cal OES) is currently conducting an assessment of the retrofit and damage. In the intern, as shown in Photo 2, the building has been fitted with temporary scaffolding on the north, south and west sides. Additionally, at the time of the EPEP follow-up survey, to allow access for repairs, the building’s placard had been revised to “Restricted Use.” Repair work is tentatively scheduled to begin in early spring 2017 (Napa Valley Publishing, 2016a). 840-844 Brown Street (Alexandria Square) Built in 1910, the Alexandria Square, also known as Plaza Hotel and Annex, is a three-story retrofitted unreinforced brick masonry building. The building was reportedly retrofitted circa 1984 to 1986. The retrofit included the installation of steel moment and braced frames within the

building’s interior and the installation of tension anchors at the diaphragm-to-wall connections. During the earthquake and as shown in Photo 3, a portion of the third-story cupola collapsed onto the sidewalk below. At these high cupola locations, steel strongbacks were anchored to the walls. However, as shown in Photo 4, the anchorage and strongback bracing was ineffective at this level. Other portions of the building were relatively undamaged. The building was initially posted “Unsafe.” However, shortly after the earthquake, the less heavily damaged portions of the building were reopened and the placard reposted to “Restricted Use.” Subsequently, the building was immediately targeted for an independent phase 2 investigation and a private structural engineering firm prepared construction documents to repair and rebuild and the damaged areas.

Photo 2. Goodman Library with temporary scaffolding as of May 23, 2016.

Photo 3. Alexandria Square following the 2014 South Napa earthquake.

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Photo 4. Ineffective steel strongback bracing in the third-story cupola.

At the time of the EPEP follow-up survey, as shown in Photo 5, the building was essentially restored and rebuilt. The building officially reopened in June of 2016. The repair costs reportedly exceeded $1 million (Napa Valley Publishing, 2015).

Photo 5. Rebuilt Alexandria Square as of May 23, 2016. 816 Brown Street (Napa Law Center Building)

Built in 1904, the Napa Law Center Building is a two-story unreinforced brick masonry building. Prior to the earthquake, the building’s owner had been considering a retrofit, as mandated by the city (Napa Municipal Code Chapter 15.110). However, at the time of the earthquake, no retrofit upgrades were constructed. As shown in Photo 6, during the earthquake, a portion of the second story south wall separated from the roof diaphragm and collapsed onto a car in the

adjacent parking lot. Immediately following the earthquake the instabilities associated with the URM walls forced the temporary closure of neighboring businesses. The building was posted, “Unsafe.” Following the erection of wooden protection barriers the surrounding buildings were reposted “Inspected.”

Photo 6. Napa Law Center building following the 2014 South Napa earthquake.

In subsequent dealings with city officials, the building’s owner was permitted to remove the front façade and redevelop the site. The plan is to number and inventory the stone blocks and then reuse the facade as part of a new five-story reconstruction on the same site. At the time of the EPEP follow-up survey, the deconstruction process, as shown in Photo 7, was progressing.

Photo 7. Deconstruction of the Napa Law Center as of May 23, 2016.

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The adjacent York Building, once home to the Napa City Council chamber was demolished as part of the redevelopment plan. Construction will reportedly require at least two years and cost approximately $20 million (Napa Valley Publishing, 2016b).

1352 2nd Street (USPS Napa Franklin Station) Built in 1933, the US Post Office Napa Franklin Station is a single-story steel frame with unreinforced brick masonry infill. It has a partial mezzanine and a basement. As shown in Photo 8, during the earthquake, the massive brick masonry piers on both ends of the building ruptured and shifted laterally. The large inclined cracks exposed damage to the underlying steel frame columns. A number of the building’s windows were also damaged. The building was posted “Unsafe.” It is located just outside the pod radius. However, given the unique damage and building type it was deemed notable for inclusion.

Photo 8. USPS Napa Franklin Station building the 2014 South Napa earthquake.

As shown in Photo 9, following the earthquake, temporary bracing was constructed around the exterior damaged piers, windows were boarded up and the location has since remained closed. In July of 2015, the USPS proposed demolishing the building. The agency estimated that quake repairs would cost $8 million, while demolition would cost only $500,000. Following a public outcry, the agency decided to place the building on the market. It was reported in July 2016 that a potential buyer had been identified. As of this writing, the buyer is currently performing due diligence on the property (Napa Valley Publishing, 2016c).

Photo 9. Temporary bracing constructed around the building’s masonry piers as of May 23, 2016.

825 Brown Street (Napa County Superior Court Building) Built in 1878, the Napa County Superior Court is a two-story retrofitted unreinforced brick masonry building. The building was reportedly partially retrofitted circa 1977. The retrofit included the installation tension anchors around the diaphragm-to-wall connections.

During the earthquake, as shown in Photo 10, the building’s URM façade sustained significant damage. Diagonal cracking occurred through many of the window spandrels and at the southeast corner, a portion of the façade collapsed. The building was posted “Unsafe” and has since remained closed.

Photo 10. Napa County Superior Court building following the 2014 South Napa earthquake.

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As shown in Photo 11, temporary bracing and a moisture barrier were constructed around the building’s exterior. Subsequent to the damage, the building was targeted for a phase 2 investigation. In addition, FEMA has tentatively agreed to pay more than $500,000 toward the $635,000 building’s earthquake insurance deductible (Napa Valley Publishing, 2016d).

Photo 11. Temporary bracing and moisture barrier constructed around the building’s exterior as of May 23, 2016.

Recently, the Napa County Board of Supervisors approved a $3.3 million contract with AECOM to design and manage the restoration project. This is in addition to the previous $2.4 million contract to assess and stabilize the damaged building. Reportedly some of the walls are so severely damaged they will have to be disassembled and reassembled, brick-by-brick. The repair work is scheduled to be complete in July of 2018 (Napa Valley Publishing, 2016e).

1130 1st Street (Gordon Building)

Built in 1928, the Gordon Building is a two-story unreinforced brick masonry structure. The building has not been retrofitted. During the earthquake, as shown in Photo 12, the building’s rear brick masonry bearing wall sustained significant damage. Diagonal cracking occurred through the supporting brick piers and lower wall. Horizontal cracking occurred at the base of the roof parapet wall and above several of the window spandrels. The building was posted “Unsafe” and has since remained closed.

As shown in Photo 13, temporary vertical bracing, parapet bracing and tension anchors at diaphragm-to-wall connections were constructed to stabilize the structure.

Photo 12. Two-story Gordon Building building following the 2014 South Napa earthquake.

Photo 13. Temporary bracing and tension anchors constructed around the building’s exterior as of May 23, 2016.

The building changed ownership in October 2013, just one year prior to the earthquake. As part of the new owner’s due diligence efforts, a 3D laser scan of the building was performed in January of 2014. After the earthquake, the building was targeted for a unique phase 2 investigation; using a supplemental 3D laser scan to compare the before and after building condition. The rescan optimized the ability to measure cracking and damage. The scanning investigation concluded that the earthquake motions expanded areas of previously known weaknesses and also created new ones (Kamimori, 2015). However, at the time of this writing, there were no known further investigation or restoration plans associated with returning the building to operational status.

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948 School Street (Napa Square Building)

Built in 2006, the Napa Square building is a three-story steel special moment frame (SMF). As shown in Photo 14, the moment frame connections utilize the reduced beam section (RBS). The frame was designed in accordance with the 2001 California Building Code and included near-fault modification factors in the determination of the lateral force coefficient. During the earthquake, notable non-structural damage occurred in many of the cast stone veneer elements surrounding the windows and entryways. In addition, issues associated with deformation compatibility damaged the exterior south wall. As shown in Photo 15, the nonbearing partition wall deformed in dramatic fashion.

Photo 14. Typical reduced beam section (RBS) moment connection in the Napa Square building.

Photo 15. Deformation damage in the building’s non-structural exterior wall.

A further phase 2 investigation determined that the south wall was inadequately attached to the structure and could not accommodate the earthquake-imposed drift. It was also reported that the south wall was required to have a three-hour fire rating given the proximity of the adjoining building. The added stiffness associated with this requirement contributed to the overall compatibility issue. It is also notable that during the phase 2 investigation, no evidence of cracking or yielding was observed in the RBS moment connections (FEMA, 2015).

The building was initially posted “Unsafe,” but was subsequently posted “Inspected.” As shown in Photo 16 at the time of the EPEP follow-up survey, the building was fully operational. The building is located outside the pod radius. However, it was deemed notable for inclusion given the damage, accessibility and structural system (SMF).

Photo 16. Napa Square building as of May 23, 2016.

1111 3rd Street (Napa County Criminal Courthouse)

Built in 1996, the Napa County Criminal Courthouse is a three-story steel eccentrically braced frame (EBF). As shown in Photo 17, the exterior is clad in a combination of precast concrete and granite. It was most likely designed under the 1991 Uniform Building Code provisions. The structural design utilized performance-based design (PBD) seismic engineering with site-specific earthquake ground motions.

The building was posted “Inspected” and was fully operational directly after the earthquake. This performance was notable but not unexpected, given the emphasis allocated to essential facilities in the corresponding building code. It was included in this paper to illustrate that properly designed buildings should achieve notable performance when subjected to ground motions below code prescribed levels.

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Photo 17. The Napa County Criminal Courthouse following the 2014 South Napa earthquake.

URM Restoration Time Frames Given their complicated nature and the construction processes associated with their restoration (i.e. brick-by-brick reconstruction), earthquake damaged URM buildings can take a significant amount of time prior to returning to fully operational status. In some cases, public versus private sector designations can affect restoration times. In terms of the this designation, the following summarizes restoration times associated with the damaged URM projects highlighted in this paper: • Public sector restoration (Goodman Library and Napa

County Superior Court buildings): approximately four years.

• Private sector fast-track restoration (Alexandria Square): slightly less than two years.

• Private sector deconstruction and redevelopment with partial restoration (Napa Law Center): four, possibly five years.

• Public to private sector transfer (USPS Napa Franklin Station): unknown final time frame.

• Private sector project restoration (Gordon Building): unknown final time frame.

Summary In the aftermath of the 2014 South Napa Earthquake, EPEP successfully deployed to the six pods in the affected region. Within the Main Street pod, the phase 1 effort was able to survey 42 buildings. Given the general lack of access, the survey was primarily focused on structural rather than non-

structural damage. Of the 42 buildings surveyed, the most common building type was URM. However, the pod also included a remarkably diverse collection of other building types. Approximately 26% of the surveyed URM buildings sustained moderate to heavy structural damage. Many of the buildings had been previously retrofitted. In general, those URM buildings without any or only partial retrofitting performed poorly. However, even several with comprehensive retrofitting sustained damage. Many of the damaged buildings have undergone or are currently undergoing some type of either phase 2 or 3 investigation. As most of these types of investigations are carried out in the private sector, the scope and findings are often not made public. To the extent possible, the phase 2 and 3 findings were summarized. In terms of restoration, most of the buildings have returned to fully operational status. However, some restoration efforts are either still ongoing or uncertain. In one case, it is hoped that a unique public to private sector transfer will lead to a successful outcome (USPS Napa Franklin Station). In still another unique case, deconstruction and redevelopment may lead to a partial restoration (Napa Law Center). In terms of newer building structural performance, two relatively newer lateral systems were part of the survey. A SMF system configured with RBS connections appears to have performed adequately despite several non-structural deformation compatibility issues (Napa Square). This example is likely one of the first actual field tests for the RBS connection. In addition, an EBF system designed to PBD standards appears to have performed exceptionally well (Napa County Criminal Courthouse). Recommendations The Main Street pod phase 1 deployment and subsequent follow-up provided the opportunity to gather data that directly relates building performance to ground motion intensity measures. The following recommendations suggest several areas of potential further study: • Compare the Main Street SMIP response spectra with

that used in the seismic design of the Napa County Criminal Courthouse. This hindsight effort can confirm assumptions and procedures used with this type of site-specific analysis.

• Compare the recorded response spectra with the lateral design used in the design of Napa Square to benchmark the rotational demands imposed on the SMF RBS connections.

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• To the extent possible, any phase 2 and 3 findings

associated with the Goodman Library and Napa County Superior Court buildings should be made public. As these are public buildings constructed and restored with government funding, the findings should be a matter of public record.

• Refer to Chapter 4 of FEMA P-1024 for further recommendations (FEMA, 2015).

Acknowledgements The authors wish to thank the EPEP volunteers who participated in the phase 1 efforts. These include Fred Turner, Brian McDonald, Marko Schotanus, and Jeff Kovach. References ATC, 2000, “Database on the Performance of Structures near Strong-Motion Recordings: 1994 Northridge, California, Earthquake, ATC-38, prepared by the Applied Technology Council for the U.S. Geological Survey, California Office of Emergency Services, and Institute for Business and Home Safety, Redwood City, California. ATC, 2012, “Seismic Performance Assessment of Buildings,” ATC P-58, prepared by the Applied Technology Council for the U.S. Geological Survey, California Office of Emergency Services, and Institute for Business and Home Safety, Redwood City, California. ASCE, 2010, “Minimum Design Loads for Buildings and Other Structures, ASCE/SEI 7-10, American Society of Civil Engineers, Reston, Virginia. ASCE, 2013, “Seismic Evaluation and Retrofit of Existing Buildings,” ASCE/SEI 41-13, American Society of Civil Engineers, Reston, Virginia. Bay Area News Group, 2014, “Napa Earthquake Stressed Other Faults.” http://www.mercurynews.com/ci_26403020/ napa-quake-stressed-other-faults. Published August 25, 2014. FEMA, 2012, “Seismic Performance Assessment of Buildings, FEMA P-58, prepared by the Applied Technology Council for the Federal Emergency Management Agency, Washington, D.C. FEMA, 2015, “Performance of Buildings and Nonstructural Components in the 2014 South Napa Earthquake,” FEMA P-1024, prepared by the Applied Technology Council for the Federal Emergency Management Agency, Washington, D.C.

GEER, 2014, “Geotechnical Engineering Reconnaissance of the August 24, 2014 M6 South Napa Earthquake,” GEER Association Report No. GEER-037, Version 1: September 15, 2014. Kamimori, S., 2015, “3D Laser Scanning Technology, Key in Preserving Historic Structures After South Napa Earthquake,” LiDAR News Magazine, Vol. 5 No. 1, 2015. Napa Valley Publishing, 2015, “Million-dollar Repairs Begin on Alexandria Square,” as appearing in the Napa Valley Register on January 23, 2015. Napa Valley Publishing, 2016a, “Property by Property, Napa Recovers From 2014 Quake,” as appearing in the Napa Valley Register on August 20, 2016. Napa Valley Publishing, 2016b, “Facade of Quake-Damaged Center Building to Become Part of Reconstruction,” as appearing in the Napa Valley Register on August 17, 2016. Napa Valley Publishing, 2016c, “New Buyer for Downtown Post Office Steps Forward,” as appearing in the Napa Valley Register on July 26, 2016. Napa Valley Publishing, 2016d, “Napa County Ends Earthquake Emergency Status,” as appearing in the Napa Valley Register on June 28, 2016. Napa Valley Publishing, 2016e, “Old Napa Courthouse Repairs To Be Finished in Summer 2018,” as appearing in the Napa Valley Register on August 12, 2016. NEHRP, 2015, “NEHRP Recommended Seismic Provisions for New Buildings and Other Structures,” prepared by the National Earthquake Hazards Reduction Program, for the Federal Emergency Management Agency, Washington, D.C. ICBO, 1997, Uniform Building Code for Building Conservation, 1997 edition, International Conference of Building Officials, Whittier, California. SEAOC, 2016, “SEAOC’s Earthquake Performance Evaluation Program (EPEP),” Structural Engineers Association of California, Sacramento, CA, http://seaoc.org/news-publications/seaoc%E2%80%99s-earthquake-performance-evaluation-program. USGS, 2014, M6.0 – 6km NW of American Canyon, California Shakemap. http:// earthquake.usgs.gov/earth quakes/eventpage/nc72282711#shakemap.

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